resurrecting an old thread of mine, I wanted to say I I'm pretty sure I didnt wire it wrong!
I tried EVERY combination of wires of which goes to the switch, which ones are taped off, and what goes with the shield to ground. Most combinations either were dead (no signal) or THINNER than what I ended up with. I also tested for if it was split, and each rail was touched with the screwdriver to asses that, and so I know it wasn't split. The out of phase, parallel, and split combinations were a lot worse than what I concluded. Instead of trashing the pickup I looked under the tape to assess which leads could possibly by the coil start and finish. Looks like green and black were switched during the pickups assembly.
I did all this rewiring with the strings on and tuned to pitch and everything so that I could hear the actual tone the pickup produced by itself
So I guess I don't want to say that GFS is a bad company, I just got a product that I believe to be defective.